1. Technical Field
This invention concerns an EEG based activation system that may be used to turn an appliance or device ON or OFF. The system may also be used to provide proportional control, which could be used, for example, to vary the sound level output of a TV or stereo sound system.
2. Background Art
Considerable interest surrounds the detection, analysis and utilization of electrical signals generated within the brain. The detection and analysis of such signals by using electrodes pressed against the scalp to sense the signals is generally referred to as electroencephalography (EEG). The application of EEG to assist in medical diagnosis and in biofeedback studies is well established. Biofeedback using EEG, in which subjects may modify their EEG waveform in response to some visual stimulus, offers promise in control applications. Powerful signal processing tools such as artificial neural networks, are being incorporated to improve the reliability of similar systems.
Though significant advances in the utilization of EEG signals for control purposes through biofeedback methods have been made in recent years, a number of difficulties remain. In situations where the control of components in the EEG waveform must be learned, the training time using biofeedback methods may span from days to months. Not all subjects are capable of learning control through biofeedback and others are unable to transfer a learned effect out of a laboratory situation. Additionally, many low impedance contacts may need to be made to the scalp to sense EEG signals. This is time consuming, attracts user hostility, and over time `good` electrical contact between one or more electrodes and the scalp may become impaired.